Fastest way to extract multiple strings?

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I have to load a huge string from stream and access some data written in it. I use substring to access the data, but its to slow . Is there a faster way maybe to convert it char array or is there a way to extract the data directly from stream? Thanks in advance.

Posted 22-Feb-11 23:06pm

apaka

Updated 22-Feb-11 23:08pm

Sergey Alexandrovich Kryukov

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How big are we talking about? I use a combination of IndexOf and Substring to great effect when parsing HTML returned from a web request. I can do a 280K file in a timely manner.

What kind of parsing needs to be done? Is the data in a predictable pattern? Can you use Split?

Posted 22-Feb-11 23:54pm

#realJSOP

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apaka 23-Feb-11 6:15am

It's about 5-30K lines. Not predictable it's a programing language. Thanks anyway.

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Sergey Alexandrovich Kryukov · Accepted Answer · 2011-02-22T23:14:00

No wonder it's slow, because you copy your original string over and over; and this is because strings are immutable.

Why, what's is that home-baked file format, so you need to read it in one string.

The best answer depends on your format. Basically, you should parse your sub-strings into list of strings as you read the file. Another option is to read all string at once and tokenize it using string.Split. Again, what delimiters to use totally depends on your format.

In all cases, you don't use the whole string or forget it after Split.

I'm not sure what way is faster, it depends on typical length of your tokens and total length. I don't think you should worry: it will be many time faster compared to what you tried.

—SA